Low carb diets and breastfeeding

By Kelly Bonyata, IBCLC

High protein, low carbohydrate diets like the Atkins diet and the South Beach diet are very popular. These diets can be helpful for diabetics and people with gluten intolerance. In these diets, protein and high fat foods are not restricted; vegetables are limited. The main difference between Atkins and South Beach seems to be that the South Beach diet is less structured and emphasizes eating healthier, mostly unsaturated fats.

The primary objections I’ve seen to these and similar diets — and this applies to everyone, not just nursing mothers — is simply the fact that they are not balanced and thus have the potential to make you feel unwell. These diets tend to be low in phytochemicals, antioxidants and folic acid. They also tend to be low in fiber and minerals (including calcium, magnesium, phosphorus & potassium), and the Atkins diet may be high in saturated fats. Because of this, long-term adherence to these diets may increase your risk for various health problems. Since some of the weight loss from these diets is simply due to water loss, dehydration is a risk if the dieter is not careful to drink plenty of water.

Some moms have found that very low carb diets decrease milk supply. Going off the diet generally brings milk volume right back up again.

This decrease in milk supply may be due to several factors:

  • Dehydration.
  • The sudden decrease in calories when mom goes on the diet. If a woman is used to a certain level of calories, an abrupt drop due to dieting (or illness) may reduce her milk supply. This sudden decrease in calories can tell mom’s body that she is in “starvation mode” and to conserve on all fronts (thus less of her body’s resources go into making milk).
  • Insufficient caloric intake. With a low carb diet, many people are not nearly as hungry — so even if you are eating to hunger, you may not be taking in enough calories to sustain a good milk supply (recommended 1800+ calories per day for the average nursing mother). Food records indicate that people following the Atkins diet self-restrict their caloric intake to less than 1700 calories per day.

Some tips for moms who wish to try a low-carb diet:

  • Wait until baby is at least 2 months old before dieting; waiting until after baby starts solids (6+ months) should be even better.
  • Drink enough water to avoid dehydration.
  • Avoid a sudden decrease in caloric intake. Start gradually.
  • Keep an eye on your caloric intake. Most moms should avoid dropping below 1800 calories per day.
  • Most sources recommend that nursing mothers avoid Phase I of the diet, and instead start with Phase II.
  • Watch for a diminished milk supply. Keep an eye on baby’s diaper output and weight gain.

More on low-carb and other diets

Can I diet while breastfeeding? @ kellymom.com

Low Carbohydrate Diets and the Breastfeeding Mother La Leche League FAQ


Eat Well,
Lose Weight
While Breastfeeding

by Eileen Behan, RD

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